Interaction of Pseudomonas aeruginosa galactophilic lectin PA-IL with pigeon egg white glycoproteins

Pseudomonas aeruginosa produces a galactophilic lectin, PA-IL, that resembles P-fimbrial adhesins of uropathogenic Escherichia coli strains in binding to human P blood group antigens. We examined, in the present study, its interaction with pigeon egg white glycoproteins carrying N-glycans with terminal Galalpha1-4Gal which inhibit the adhesion of P-fimbriae. For comparison, the lectin concanavalin A (Con A) and additional avian egg whites (of hen and quail) were also examined. The results obtained in both hemagglutination inhibition and Western blot analyses showed that PA-IL, unlike Con A, preferentially reacted with the pigeon egg white glycoproteins. These results, which confirmed PA-IL similarity in sugar specificity to E. coli P-fimbriae, demonstrated the advantage of this purified lectin for representing P-type and additional galactophilic microbial adhesins unavailable in purified stable form, in Western blot analyses.     

beta-Sulfonamido gonadotropin-releasing hormone analogs: synthesis and evaluation of several parent hormone properties.

With the aim of producing long-acting analogs of gonadotropin releasing hormone (GnRH), four analogs, containing -X(6) (aa)psi(CH(2)SO(2)NH)-Leu(7) building unit (X(aa)=Gly, Ala, Val or Phe), and a reduced-size analog [Des-Tyr(5)]-GnRH which includes the unit Phe(5)psi(CH(2)SO(2)NH)-Leu(6), and [beta-Ala(6)]-GnRH were synthesized. The peptides were evaluated for their capacity to induce LH-release from rat pituitary cells and to withstand proteolysis by pituitary-derived enzymes, compared with the parent peptide GnRH. Albeit stable toward enzymatic degradation, the sulfonamido containing peptides were only marginally bioactive. [beta-Ala(6)]-GnRH, however, induced LH-release and bound to pituitary receptors nearly as efficiently as GnRH. This analog was also highly stable toward proteolysis suggesting that it may serve as a long-acting GnRH-analog.     

Toward a comprehensive temperature-sensitive mutant repository of the essential genes of Saccharomyces cerevisiae

The Saccharomyces cerevisiae gene deletion project revealed that approximately 20% of yeast genes are required for viability. The analysis of essential genes traditionally relies on conditional mutants, typically temperature-sensitive (ts) alleles. We developed a systematic approach (termed "diploid shuffle") useful for generating a ts allele for each essential gene in S. cerevisiae and for improved genetic manipulation of mutant alleles and gene constructs in general. Importantly, each ts allele resides at its normal genomic locus, flanked by specific cognate UPTAG and DNTAG bar codes. A subset of 250 ts mutants, including ts alleles for all uncharacterized essential genes and prioritized for genes with human counterparts, is now ready for distribution. The importance of this collection is demonstrated by biochemical and genetic screens that reveal essential genes involved in RNA processing and maintenance of chromosomal stability.     

Genetic relationships betweenLupinus pilosus andL. palaestinus (Fabaceae)

Lupinus pilosus Murr. andL. palaestinus Boiss., are both East Mediterranean annuals, greatly resemble each other in morphology, and have the same chromosome number (2n = 42). Some fertile hybrids can be formed by artificial hybridization or under unusual habitat conditions. Isolation in nature between the species is, however, maintained by prevalent selfing, partial reproductive barriers and genic imbalance, together with differences in ecological requirements. It is suggested that this speciation pattern which includes little morphological and hardly any chromosomal divergence might have occurred in other cases of edaphic vicariants too.     

Micropatterned thin film honeycomb materials from regiospecifically modified cellulose

Thin film honeycomb materials were prepared from regioselectively modified celluloses. The method uses water condensation at the surface of a cellulosic solution as an ordered template to form honeycomb structures. Pore size and distribution is controlled by several factors, one of which is the hydrophilicity of the cellulosic used. The amphiphilic nature of the celluloses was modified with varying lengths of ethylene glycol side chains using 2,6-thexyldimethylsilyl cellulose. It was found that the side chains do affect the honeycomb formation, with longer ethylene glycol chains leading to increased pore uniformity but having little influence on the pore size.     

Ferritin-bearing lymphocytes and T-cell levels in peripheral blood of patients with breast cancer

Summary Peripheral blood lymphocytes bearing surface ferritin and thymus-dependent lymphocyte (T cell) levels were determined in 15 breast cancer patients in stage I–II, 5 in stage III, 10 with benign breast disease, 4 with Thalassaemia, and 25 normal controls. The results of this study demonstrate that a subpopulation of lymphocytes (16.6%) bearing surface ferritin was found in patients with breast cancer in stage I–II. None were demonstrated in patients with either benign breast disease, or with Thalassaemia, the latter known to have high serum ferritin levels, and almost none (1.7%) in normal individuals. A significant decrease in the percentage of ERFC as compared with the percentage of T cells, determined with anti-T cell antiserum (P<0.01), was observed in patients with breast cancer in stage I–II. Yet, the mean T-cell percentage in this group of patients was significantly higher than the mean percentage of T cells in normal controls (P<0.01). In patients with benign breast disease, the percentage of T cells corresponded to the percentage of ERFC and did not significantly differ from those in normals. Stage III breast cancer patients seem to constitute a biologically distinct group, since the ferritin-positive lymphocyte subpopulation disappeared and the percentage of ERFC and T cells returned to the values of normal controls.Overnight incubation of lymphocytes from patients exhibiting a ferritin-positive lymphocyte subpopulation in culture media containing 20% FCS resulted in the removal of ferritin from the surface of the cells and in restoration of the percentage of ERFC.     

The annual species ofAdonis (Ranunculaceae)—a polyploid complex

The five annual species ofAdonis L., sect.Adonis, growing in Israel, form a series of diploid, tetraploid and hexaploid species. Their somatic chromosome numbers are 2n = 16 inA. annua L.,A. dentata Del. andA. palaestina Boiss., 2n = 32 inA. microcarpa DC., 2n = 48 inA. aestivalis L.; counts forA. dentata, A. palaestina andA. microcarpa are new records. There are indications that alloploidization may have been involved in the process of speciation in sect.Adonis. A taxonomic survey of the 8 species of the section reveals that a higher ploidy level is usually combined with a larger distribution area.     

Dominance and non-complementation among pink-adenineless mutants of Schizophyllum commune involving two discrete genes

Summary In Schizophyllum commune, adenineless mutations conferring pink color fell into two loosely linked loci, ad-4 and ad-7. The mutations were tested for dominance and complementation in dikaryons, and several of the ad-7 mutations were found to be partly dominant over their wild allele and noncomplementary with mutations of the ad-4 locus. The dominance and at least one case of intergenic noncomplementation were verified by quantitative tests.This research was partly supported by the U.S. Department of Agriculture Grant No. A10-CR-66.     

Competitive ability as a function of sensitivity to the environment I. Competition betweenTribolium castaneum andTribolium confusum in a deteriorating environment

Summary Tribolium castaneum lines selected for high and for low sensitivity to the environment were observed in pure strain culture and in mixed 1∶1 cultures withTribolium confusm. Since the medium was not refreshed during the experiment, the environment was continuously deteriorating and ultimately both species became extinct. Both time until extinction and total dry weight were used as a measure of competitive ability. AllTribolium castaneum lines showed higher competitive ability thanTribolium confusum. As interference was noted in all the mixed cultures, competition here demonstrates both exploitation and interference. Comparisons between theT. castaneum lines indicates higher competitive ability for lines with shorter developmental time.